There has to be a reason for this behavior...It sounds like a chemical imbalance as Bi-polar behavior. I really don't aggresive behavior back toward her as to start spraying her with water is the answer...
I have to agree with putting her on a anti-depressant for a while and see if this corrects your problem. Dogs can sense fear so put on some good leather gloves (welding gloves would proably offer better protection) and try to reassure her with compassion.
